Patent GB-449760-A (GB)
Title: Improvements relating to apparatus for separation of minerals
IPC: B03B5/18
Filed: 1934-12-29
Abstract: 449,760. Separating or classifying solid materials. STOKES, R. O., 815, Salisbury House, London Wall, and ALLAN, J. C., c/o British Non-Ferrous Mining Corporation, Ltd., 19, Basinghall Street, both in London. Dec. 29, 1934, No. 37263. [Classes 82 (ii) and 117] In apparatus for separating or classifying minerals in which the material is supported on a perforated table immersed in water, vertical reciprocating motion is imparted to the table and the direction of movement of the table is determined by radius arms attached to the table and to stationary pivots, means being provided for adjusting the position of the stationary pivots during operation to vary the relative values of the horizontal and vertical components of movement of the table. The table is preferably driven through mechanism such as a drag link which gives a higher speed of movement on the down stroke than on the upward stroke. In the form shown in Figs. 1, 2, 3 and 6, the perforated table 5 is divided into three sections, each formed of a plurality of box-like structures 38-41, Fig. 3, with sloping perforated tops, held in position by boards 63 and wedges 42. The tops of the structures 38 and 39 are flat and those of the structures 40 and 41 slope downwardlv towards the middle. Between each pair of sections is a sliding member 47 moved by a rod 49 actuated by quadrant mechanism and having an inverted V-shaped notch. The member is guided by a strap 48 adjustable in height and the discharge aperture 47 formed by the notch can therefore be adjusted as desired, the heavy material passing through the aperture being directed downwardly by a guide plate 93. Four hoppers 4 are formed below the screen in the casing 1 in which the screen is reciproacted, an oblique baffle being provided to direct fine material passing through the screen into the hopper under the feed end of the screen. In the form shown in Fig. 9, the screen surface is continuous and is divided into compartments by transverse partitions 71, apertures 72 being provided in front of the partitions. The size of the apertures is adjusted by wedge-shaped valves 73 which can be raised or lowered by hand wheels 78. Alternatively as shown in Fig. 13, the size of the apertures may be adjusted by flap valves 88 connected to a link 90 which can be raised or lowered by the lever 92. According to the Provisional Specification the table may be built up of a number of plates with transverse gaps between them, curved upward extensions being provided on the far sides of the gaps to face the moving material and remove the lower stratum. Either the extensions or the screen sections may be adjustable to vary the size of the apertures. The screen is suspended by links 75, Fig. 2, the lower ends of which engage a shaft 30 attached to extensions 31 of the screen frame. The upper ends of the links engage a bar 29 at the lower end of an upright bar 25 provided with parallel-link mechanism 26, 27, and pivoted at 24 to a connecting rod 23 operated by a crank. The crank shaft carries a second crank which is coupled by a drag link to a driven shaft arranged so that the downward movement of the screen is more rapid than the upward movement. The shaft 30 has pivoted to it a pair of guide links 32 journalled on a cranked bar 34 the position of which can be adjusted by a nut 37 on a pivoted rod, the nut being integral with a ball which is held by a socket forming part of the crank 36 on the bar 34. By adjusting the position of the bar 34 the screen may be given either a vertical motion or any desired combined vertical and horizontal motion. According to the Provisional Specification the pivots of the guide links may be on a second pair of links which turn about fixed pivots. In the form shown in Fig. 7, the driving mechanism comprises a pair of levers 58, 59 pivoted at 60 and 61 respectively and joined at their inner ends by a link 57 driven by a pitman 23 pivoted at 56 to the centre of the link The pitman is actuated through crank mechanism and a drag link as described with reference to Fig. 2. The outer end of each lever has a screw 62 with a nut to which is pivoted a suspending rod 65, the vertical stroke of the table being adjusted by movement of the nuts. The shafts 30 to which the lower ends of the suspending rods 65 are pivoted are provided with guiding mechanism comprising links 67 pivoted at 68 on webs integral with tubes 69 the position of which can be adjusted. Devices for sampling the material passing through the adjustable apertures may be provided, the devices preferably comprising a spoon device which is slidable and rotatable and can be withdrawn to remove the sample during operation.